Engine apparatus

ABSTRACT

An engine apparatus includes an engine and an exhaust gas purifier. The engine includes an intake manifold and an exhaust manifold. The exhaust gas purifier is configured to purify exhaust gas of the engine and disposed on an upper side of the engine through a mounting base. The mounting base includes an intake-side bracket and an exhaust-side bracket, which support one end of the exhaust gas purifier. One end of the intake-side bracket and one end of the exhaust-side bracket are fastened to each other. The other end of the intake-side bracket and the other end of the exhaust-side bracket are coupled to the engine side.

TECHNICAL FIELD

The present invention relates to an engine apparatus mounted on aworking machine such as a construction civil-engineering machine, anagricultural machine, and an engine generator.

BACKGROUND OF THE INVENTION

Recently, high-order emission control has been applied to diesel engines(hereinafter simply referred to as engine). Accordingly, it has beendesired to mount an exhaust gas purifier to purify atmosphericpollutants contained in exhaust gas on a working machine such as aconstruction civil-engineering machine, an agricultural machine, and anengine generator on which an engine is mounted. As an exhaust gaspurifier, a diesel particulate filter (hereinafter referred to as DPF)to collect particulate matter and such substances contained in exhaustgas has been known (see patent documents 1 to 3).

RELATED ART DOCUMENTS

-   Patent Document 1: Japanese Unexamined Patent Application    Publication No. 2000-145430.-   Patent Document 2: Japanese Unexamined Patent Application    Publication No. 2003-27922.-   Patent Document 3: Japanese Unexamined Patent Application    Publication No. 2010-71176.

In the DPF, particulate matter is accumulated in a soot filter withyears of service. There is a technique of burning and removing suchparticulate matter at the time of driving the engine to restore the sootfilter. It has been known that restoration of the soot filter occurswhen an exhaust gas temperature is equal to or higher than a restorabletemperature (approximately 300° C., for example). Consequently, thetemperature of exhaust gas passing the DPF is desirably equal to orhigher than the restorable temperature. In view of this, since longbefore, there has been a demand for mounting the DPF at a position wherethe exhaust gas temperature is high, that is, directly on the engine.

However, when the DPF is attached to the engine, vibration of the enginewhen driven may be unfortunately transmitted to the exhaust gas purifierdirectly. Unless an appropriate attachment configuration of the DPF isconsidered, there is a risk that such vibration will damage a dieseloxidation catalyst and the soot filter accommodated in the DPF.

A space for mounting an engine depends on a kind of a working machine onwhich the engine is mounted. In most cases, recent demand for weight andsize reduction restricts the mounting space (makes the mounting spacesmall). In view of this, when the DPF is directly mounted on the engine,it is required to provide a layout of the DPF as compact as possible.

SUMMARY OF THE INVENTION

It is a technical object of the present invention to provide an engineapparatus improved in view of the above-described current circumstances.

According to the invention, an engine apparatus includes an engine andan exhaust gas purifier. The engine includes an intake manifold and anexhaust manifold. The exhaust gas purifier is configured to purifyexhaust gas of the engine and disposed on an upper side of the enginethrough a mounting base. The mounting base includes an intake-sidebracket and an exhaust-side bracket, which support one end of theexhaust gas purifier. One end of the intake-side bracket and one end ofthe exhaust-side bracket are fastened to each other. The other end ofthe intake-side bracket and the other end of the exhaust-side bracketare coupled to the engine side.

According to the invention, in the engine apparatus, the one end of theexhaust gas purifier is coupled to one of the intake-side bracket andthe exhaust-side bracket.

According to the invention, in the engine apparatus, a provisionalfastening notch is formed in one of the intake-side bracket and theexhaust-side bracket. An engagement shaft disposed on the other of theintake-side bracket and the exhaust-side bracket is to engage in theprovisional fastening notch.

According to the invention, in the engine apparatus, a lower end of ahanger configured to lift the engine is fastened to one of theintake-side bracket and the exhaust-side bracket.

According to the invention, the engine apparatus, further includes arotation angle detection member and an output shaft pulser. The rotationangle detection member is configured to detect a rotation angle of anoutput shaft of the engine. The output shaft pulser is disposed on aflywheel of the engine. A mounting plate supporting an engine starter isdisposed on one side portion of the engine on the flywheel side andlocated between the one side portion of the engine and the flywheel. Therotation angle detection member is disposed on the mounting plate andopposed to a side surface of the output shaft pulser facing the one sideportion of the engine.

According to the invention, in the engine apparatus, a recessed portionis formed in an inner surface of the flywheel close to the engine. Theoutput shaft pulser is disposed in the recessed portion. A distal end ofthe rotation angle detection member is inserted into the recessedportion.

According to the invention, in the engine apparatus, a ring near toengage with the engine starter is disposed on an outer peripheralportion of the inner surface of the flywheel close to the engine. Theoutput shaft pulser and the ring gear are fitted and secured to theflywheel from the same side.

According to the invention, the mounting base includes the intake-sidebracket and the exhaust-side bracket to support one end of the exhaustgas purifier. One end of the intake-side bracket and one end of theexhaust-side bracket are fastened to each other whereas the other end ofthe intake-side bracket and the other end of the exhaust-side bracketare coupled to the engine side. Consequently, the mounting base isseparated into the intake-side bracket and the exhaust-side bracket.While the brackets as single parts are reduced in weight, the bracketsare fastened to each other to secure a sufficient strength of support,which enables the exhaust gas purifier to be stably mounted on theengine. This therefore prevents degradation and damage of the exhaustgas purifier due to vibration of the engine, for example. Thus,durability of the exhaust gas purifier is improved.

According to the invention, one end of the exhaust gas purifier iscoupled to one of the intake-side bracket and the exhaust-side bracket.Consequently, the exhaust gas purifier is mounted on or dismounted fromthe engine while one of the intake-side bracket and the exhaust-sidebracket is coupled to the one end of the exhaust gas purifier. Thisimproves assembling workability of the exhaust gas purifier with respectto the engine. Moreover, the other of the intake-side bracket and theexhaust-side bracket may be used for, for example, a mounting base ofthe hanger to hang the engine.

According to the invention, the provisional fastening notch is formed inone of the intake-side bracket and the exhaust-side bracket. Theengagement shaft, which is disposed on the other of the intake-sidebracket and the exhaust-side bracket, is to engage with the provisionalfastening notch. Therefore, the engagement of the engagement shaft andthe provisional fastening notch facilitates positioning of one of thebrackets with respect to the other bracket, and at the same time,positioning of the exhaust gas purifier with respect to the engine.Furthermore, there is no need to execute assembling operation such asbolt fastening and disassembling operation while sustaining the wholeweight of the exhaust gas purifier. This significantly reduces labor andtime at the time of mounting and dismounting operation of the exhaustgas purifier and assembling and disassembling operation of the exhaustgas purifier.

According to the invention, the lower end of the hanger to lift theengine is fastened to one of the intake-side bracket and theexhaust-side bracket. Consequently, one of these two brackets, which arehighly rigid components to support the exhaust gas purifier, is alsoused for a fastening portion of the hanger. This reduces the number ofcomponents, and at the same time, the hanger is firmly fastened to theengine (the coupling strength of the hanger with respect to the engineis secured).

According to the invention, the engine apparatus includes the rotationangle detection member and the output shah pulser. The rotation angledetection member detects a rotation angle of the output shaft of theengine. The output shaft pulser is disposed on the flywheel of theengine. The mounting plate supporting the engine starter is disposed onone side portion of the engine on the flywheel side. The mounting plateis disposed between the one side portion of the engine and the flywheel.The rotation angle detection member is disposed on the mounting plate.The rotation angle detection member is opposed to the side surface ofthe output shaft pulser that faces the one side portion of the engine.Consequently, the rotation angle detection member is supported on themounting plate having a weight smaller than a flywheel housing, and theheavy flywheel housing is unnecessary. Therefore, the engine is reducedin weight and size.

According to the invention, the recessed portion is formed in the innersurface of the flywheel close to the engine. The output shaft pulser isdisposed in the recessed portion. The distal end of the rotation angledetection member is inserted into the recessed portion. Consequently,the output shaft pulser and the rotation angle detection member arearranged on the flywheel and the mounting plate in a compact space. Thisdecreases the thickness of the flywheel and the mounting plate in thedirection of the output shaft, thus contributing to space saving of theengine and surrounding components.

According to the invention, the ring gear to engage with the enginestarter is disposed on the outer peripheral portion of the inner surfaceof the flywheel close to the engine. The output shaft pulser and thering gear are fitted and secured to the flywheel from the same side.Consequently, the output shaft pulser and the ring gear are locatedbetween the flywheel and the mounting plate. This minimizes entering ofdust and foreign matter into the vicinity of the output shaft pulser andthe ring gear.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of an engine according to an embodiment;

FIG. 2 is a rear view of the engine;

FIG. 3 is a left side view of the engine;

FIG. 4 is a right side view of the engine;

FIG. 5 is a plan view of the engine;

FIG. 6 is an upper-left perspective view of the engine;

FIG. 7 is a right rear perspective view of the engine;

FIG. 8 is an upper-left front perspective view of a cylinder head and anexhaust gas purifier, illustrating a positional relationship between thecylinder head and the exhaust gas purifier;

FIG. 9 is an upper-right perspective view of the cylinder head and theexhaust gas purifier, illustrating a positional relationship between thecylinder head and the exhaust gas purifier;

FIG. 10 is an enlarged front view of brackets bodies, the exhaust gaspurifier, and the cylinder head, illustrating a state of attachment ofthe bracket bodies and the exhaust gas purifier to the cylinder head;

FIG. 11 is an enlarged left front perspective view of the bracketbodies, the exhaust gas purifier, and the cylinder head, illustratingthe state of attachment of the bracket bodies and the exhaust gaspurifier to the cylinder head;

FIG. 12 is an enlarged right rear perspective view of the bracketbodies, the exhaust gas purifier, and the cylinder head, illustratingthe state of attachment of the bracket bodies and the exhaust gaspurifier to the cylinder head;

FIG. 13 is an exploded perspective view of an intake-side bracket;

FIG. 14 is an exploded perspective view of the whole bracket bodies;

FIG. 15 is an exploded perspective view for describing a state ofattachment of the exhaust gas purifier;

FIG. 16 is an upper front perspective view of the cylinder head and theexhaust gas purifier, illustrating a positional relationship between thecylinder head and the exhaust gas purifier;

FIG. 17 is a rear perspective view of the engine from which a flywheelis omitted; and

FIG. 18 is an enlarged plan cross-sectional view of the flywheel andsurrounding components.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be described below withreference to the drawings. First, referring to FIGS. 1 to 7, descriptionwill be made on a schematic configuration of a common-rail engine 1 inthis embodiment. It should be noted that in the following description,both sides in an axial direction of an output shaft 3 (portions on bothsides of the output shaft 3) will be referred to as left and right. Aside on which a cooling fan 9 is disposed will be referred to as thefront side. A side on which a flywheel 11 is disposed will be referredto as the rear side. A side on which an exhaust manifold 7 is disposedwill be referred to as the left side. A side on which an intake manifold6 is disposed will be referred to as the right side. For convenience'sake, these are regarded as references of a relationship of left, right,front, rear, upper, and lower positions in the engine 1.

As shown in FIGS. 1 to 7, the engine 1 as a prime mover is mounted on aworking machine such as a construction civil-engineering machine and anagricultural machine. The engine 1 includes a continuous-regenerationexhaust gas purifier 2 (DPF). The exhaust gas purifier 2 removesparticulate matter (PM) contained in exhaust gas emitted from the engine1 and also reduces carbon monoxide (CO) and hydrocarbon (HC) containedin the exhaust gas.

The engine 1 includes a cylinder block 4 accommodating the output shaft3 (crank shaft) and pistons (not shown). A cylinder head 5 is mounted onthe cylinder block 4. The intake manifold 6 is disposed on the rightside surface of the cylinder head 5. The exhaust manifold 7 is disposedon the left side surface of the cylinder head 5. That is, the intakemanifold 6 and the exhaust manifold 7 are separately located on bothside surfaces of the engine 1 along the output shaft 3. A head cover 8is disposed on the upper surface of the cylinder head 5. The cooling fan9 is disposed on a side surface of the engine 1 that intersects theoutput shaft 3, specifically, on the front surface of the cylinder block4. A mounting plate 10 is disposed on the rear surface of the cylinderblock 4. The flywheel 11 is disposed over the mounting plate 10.

The flywheel 11 is axially supported on the output shaft 3. Motive powerof the engine 1 is transmitted to an operation unit of the workingmachine through the output shaft 3. An oil pan 12 is disposed on thelower surface of the cylinder block 4. Lubrication oil in the oil pan 12is supplied to lubrication portions of the engine 1 through an oilfilter 13 disposed on the right side surface of the cylinder block 4.

A fuel supply pump 14 to supply fuel is attached to the right sidesurface of the cylinder block 4 that is above the oil filter 13 (belowthe intake manifold 6). The engine 1 includes injectors 15 for fourcylinders provided with electromagnetic-switch control fuel injectionvalves (not shown). Each of the injectors 15 is coupled to a fuel tank(not shown) mounted on the working machine through the fuel supply pump14, a cylindrical common rail 16, and a fuel filter (not shown).

Fuel in the fuel tank is supplied under pressure from the fuel supplypump 14 to the common rail 16 through the fuel filter (not shown). Thehigh-pressure fuel is accumulated in the common rail 16. By switchcontrol of the fuel injection valves of the injectors 15, thehigh-pressure fuel in the common rail 16 is injected from the injectors15 to the respective cylinders of the engine 1. It should be noted thatan engine starter 18 is disposed on the mounting plate 10. A pinion gear127 of the engine starter 18 meshes with a ring gear 124 of the flywheel11 (see FIGS. 16 and 17). When the engine 1 is started, torque of thestarter 18 makes the ring gear 124 of the flywheel 11 rotate to causethe output shaft 3 to start rotating (to execute so-called cranking).

A coolant pump 21 is disposed on the front side of the cylinder head 5(on the cooling fan 9 side) to be coaxial with a fan shaft of thecooling fan 9. An alternator 23 is disposed on the left side of theengine 1, specifically on the left side of the coolant pump 21. Thealternator 23 serves as a generator to generate electricity by motivepower of the engine 1. Through a cooling fan driving V belt 22, rotationof the output shaft 3 drives not only the cooling fan 9 but also thecoolant pump 21 and the alternator 23. A radiator 19 (see FIGS. 3 and 4)mounted on the working machine contains coolant. The coolant pump 21 isdriven to supply the coolant to the cylinder block 4 and the cylinderhead 5, thereby cooling the engine 1.

Engine leg attachment portions 24 are disposed on the left and rightside surfaces of the oil pan 12. Engine legs (not shown) includingrubber vibration isolators are respectively fastened by bolts to theengine leg attachment portions 24. In this embodiment, the oil pan 12 isclamped by a pair of left and right engine support chassis 25 in theworking machine. The engine leg attachment portions 24 on the oil pan 12side are fastened by bolts to the engine support chassis 25. Thus, boththe engine support chassis 25 of the working machine support the engine1.

As shown in FIGS. 4 to 7, an air cleaner (not shown) is coupled to aninlet portion of the intake manifold 6 through an EGR device 26 (exhaustgas recirculation device). The EGR device 26 is mainly disposed on theright side of the engine 1, specifically, on the right side of thecylinder head 5. Fresh air (outside air) drawn into the air cleaner isdusted and purified by the air cleaner. Then, through the EGR device 26,the fresh air is supplied to the intake manifold 6 to be supplied to thecylinders of the engine 1.

The EGR device 26 includes an EGR main body case 27, an intake throttlemember 28, a recirculation exhaust gas pipe 30, and an EGR valve member31. The EGR main body case 27 mixes part of exhaust gas of the engine 1(EGR gas) with fresh air and supplies the mixture to the intake manifold6. The intake throttle member 28 communicates the EGR main body case 27with the air cleaner. The recirculation exhaust gas pipe 30 is coupledto the exhaust manifold 7 through an EGR cooler 29. The EGR valve member31 communicates the EGR main body case 27 with the recirculation exhaustgas pipe 30.

Specifically, the intake throttle member 28 is coupled to the intakemanifold 6 through the EGR main body case 27. An outlet side of therecirculation exhaust gas pipe 30 is coupled to the EGR main body case27. An inlet side of the recirculation exhaust gas pipe 30 is coupled tothe exhaust manifold 7 through the EGR cooler 29. An opening degree ofan EGR valve in the EGR valve member 31 is controlled to regulate anamount of supply of EGR gas to the EGR main body case 27. It should benoted that the EGR main body case 27 is detachably fastened by bolts tothe intake manifold 6.

In the above-described configuration, fresh air is supplied from the aircleaner into the EGR main body case 27 through the intake throttlemember 28 whereas the EGR gas is supplied from the exhaust manifold 7into the EGR main body case 27. After the fresh air from the air cleanerand the EGR gas from the exhaust manifold 7 is mixed in the EGR mainbody case 27, the mixed gas is supplied to the intake manifold 6. Partof exhaust gas emitted from the engine 1 to the exhaust manifold 7 ismade to flow back from the intake manifold 6 to the engine 1. Thislowers the maximum combustion temperature at the time of high-loaddriving, thus decreasing an emission volume of NOx (nitrogen oxide) fromthe engine 1.

On the upper side of the engine 1, the exhaust gas purifier 2 isdisposed above the exhaust manifold 7, specifically, on the left side ofthe cylinder head 5 and above the exhaust manifold 7. In this case, theposture of the exhaust as purifier 2 is set in such a manner that thelongitudinal direction of the exhaust gas purifier 2 is parallel to theoutput shaft 3 of the engine 1. A purification inlet pipe 36 is disposedon an outer peripheral portion of the exhaust gas purifier 2 on theexhaust upstream side. The purification inlet pipe 36 is coupled to theoutlet portion of the exhaust manifold 7. Exhaust gas discharged fromthe cylinders of the engine 1 to the exhaust manifold 7 is emitted tothe outside through such components as the exhaust as purifier 2.

Next, referring to FIGS. 8 to 12 in addition to FIGS. 1 to 7, aconfiguration of the exhaust gas purifier 2 will be described. Theexhaust gas purifier 2 includes a purification casing 38 provided withthe purification inlet pipe 36. Inside of the purification casing 38, adiesel oxidation catalyst 39 and a soot filter 40 are arranged in seriesin a direction of movement of exhaust gas. The diesel oxidation catalyst39 is, for example, platinum, which generates nitrogen dioxide (NO₂).The soot filter 40 has a honeycomb structure to continuously oxidizesand removes collected particulate matter (PM) at relatively lowtemperature. The diesel oxidation catalyst 39 and the soot filter 40 areequivalent to a gas purification filter accommodated in the purificationcasing 38. It should be noted that, for example, a muffler or a tailpipe is coupled to an exhaust gas outlet 41 of the purification casing38 through an exhaust pipe. Thus, the exhaust gas is emitted from theexhaust gas outlet 41 to the outside through the muffler or tail pipe.

In the above-described configuration, nitrogen dioxide (NO₂) generatedby oxidation function of the diesel oxidation catalyst 39 is drawn intothe soot filter 40. Particulate matter in exhaust gas of the engine 1 iscollected by the soot filter 40, and the particulate matter iscontinuously oxidized and removed by nitrogen dioxide (NO₂). Thisensures not only removal of the particulate matter (PM) from the exhaustgas of the engine 1 but also decreases of the carbon monoxide (CO)content and the hydrocarbon (HC) content in the exhaust gas of theengine 1.

The purification inlet pipe 36 is disposed on the outer peripheralportion of the purification casing 38 on the exhaust upstream side. Inthis embodiment, the purification inlet pipe 36 is formed to have a halfcylindrical shape opening upwardly. A rectangular upwardly opening endportion of the purification inlet pipe 36 on a large diameter side iswelded to an outer peripheral portion of the purification casing 38 tocover an exhaust gas inflow port (not shown) formed in the purificationcasing 38. The exhaust gas intake side of the purification inlet pipe 36is located in the center of the longitudinal direction of thepurification casing 38. The exhaust gas intake side of the purificationinlet pipe 36 is fastened to the outlet portion of the exhaust manifold7.

A lid member 42 is welded on an end portion of the purification casing38 at the exhaust downstream side. The end portion of the purificationcasing 38 at the exhaust downstream side is covered with the lid member42. An exhaust gas outlet 41 is opened approximately in the center ofthe lid member 42. An inlet-side lid member 43 is welded on an endportion of the purification casing 38 at the exhaust upstream side. Theend portion of the purification casing 38 at the exhaust upstream sideis covered with the inlet-side lid member 43.

The purification casing 38 includes an exhaust gas temperature sensor 57of a thermistor. This embodiment provides a pair of exhaust gastemperature sensors 57 from each of which a sensor pipe 57 a extends.Detection portions on distal ends of the sensor pipes 57 a are insertedinto the exhaust upstream side from the diesel oxidation catalyst 39 andbetween the diesel oxidation catalyst 39 and the soot filter 40 in orderto detect exhaust gas temperatures in the spaces. The exhaust gastemperature sensors 57 convert the exhaust gas temperatures intoelectric signals to be output to an engine controller (not shown).

An exhaust pressure sensor 44 is attached to the purification casing 38.The exhaust pressure sensor 44 detects a difference between pressures ofexhaust gas on the upstream side and the downstream side of the sootfilter 40. The exhaust pressure sensor 44 converts the pressuredifference of the exhaust gas into electric signals to be output to theengine controller (not shown). Based on the pressure difference of theexhaust gas between the upstream side and the downstream side of thesoot filter 40, an amount of accumulation of particulate matter in thesoot filter 40 is calculated to grasp a state of clogging in the sootfilter 40.

A sensor fastening portion 46 with through holes is disposed on anintermediate clamping flange 45 of the purification casing 38 andlocated on an outer peripheral portion of the purification casing 38 onthe head cover 8 side. The exhaust pressure sensor 44 integral with anelectric wiring connector 44 a and electric wiring connectors 57 b ofthe exhaust gas temperature sensors 57 are attached to a sensor bracket58. In this case, the sensor bracket 58 is made of an approximatelyL-shaped aluminum plate and reduced in weight. The exhaust pressuresensor 44 is disposed on a horizontal plate portion of the sensorbracket 58 through a heat insulating and vibration isolating sheet (notshown). The electric wiring connectors 57 b of the exhaust gastemperature sensors 57 are disposed in the longitudinal direction on avertical plate portion of the sensor bracket 58 through a heatinsulating and vibration isolating sheet (not shown). With thisconfiguration, the electric wiring connectors 44 a and 57 b of thesensors 44 and 57 are gathered in one place to readily concentratewiring with respect to the electric wiring connectors 44 a and 57 b.Wiring operation is also facilitated.

One end of an upstream-side sensor pipe 47 and one end of adownstream-side sensor pipe 48 are coupled to the exhaust pressuresensor 44. The purification casing 38 is provided with upstream-side anddownstream-side sensor pipe bosses 49 and 50 with the soot filter 40 inthe purification casing 38 interposed between the sensor pipe bosses 49and 50. Through pipe fitting bolts 53, fastening bosses 51 and 52disposed on the other end of the sensor pipe 47 and the other end of thesensor pipe 48 are respectively fastened to the sensor pipe bosses 49and 50.

In the above-described configuration, a difference between an exhaustgas pressure at the upstream (inflow) side of the soot filter 40 and anexhaust gas pressure at the downstream (outflow) side of the soot filter40 (differential pressure of the exhaust gas) is detected by the exhaustpressure sensor 44. The residual amount of particulate matter in theexhaust gas collected by the soot filter 40 is proportional to thedifferential pressure of the exhaust gas. Consequently, when theresidual amount of particulate matter in the soot filter 40 becomesequal to or larger than a predetermined value, restoration control(control for increasing the exhaust gas temperature, for example) isexecuted based on a detection result of the exhaust pressure sensor 44.Thus, the amount of the particulate matter in the soot filter 40 isreduced. Moreover, when the residual amount of the particulate matterfurther increases beyond a restoration controllable range, thepurification casing 38 is detached and disassembled to clean the sootfilter 40. Thus, maintenance work is performed to manually remove theparticulate matter.

As described above, the electric wiring connectors 44 a and 57 b for thesensors 44 and 57 (detection members) with respect to the exhaust gaspurifier 2 are located on the outer peripheral portion of the exhaustgas purifier 2 on the head cover 8 side. This allows the electric wiringconnectors 44 a and 57 b to be positioned at a height approximatelyequal to or lower than an upper end of the exhaust gas purifier 2.Consequently, with respect to the overall height of the engine 1including the exhaust gas purifier 2, an influence of the arrangement ofthe electric wiring connectors 44 a and 57 b is minimized or eliminated.This arrangement is effective for reducing the overall height of theengine 1 assembled with the exhaust gas purifier 2 as much as possible,which contributes to size reduction of the engine 1.

The exhaust gas purifier 2 is disposed on the upper side of the engine 1and above the exhaust manifold 7, and supported on the cylinder head 5and the exhaust manifold 7 in a posture to extend parallel to the outputshaft 3 of the engine 1. This enables shipment of the engine 1 afterassembled with the exhaust gas purifier 2. Using the cylinder head 5 andthe exhaust manifold 7, which are components having high rigidity of theengine 1, the exhaust gas purifier 2 is supported highly rigidly toprevent damage of the exhaust gas purifier 2 due to vibration, forexample. Furthermore, the exhaust gas purifier 2 is communicable withthe exhaust manifold 7 at close range to maintain the exhaust gaspurifier 2 at appropriate temperature. This ensures maintenance of highpurification performance of the exhaust gas. As a result, the exhaustgas purifier 2 is reduced in size.

Next, referring to FIGS. 8 to 16, a configuration of assembling theengine 1 with the exhaust gas purifier 2 will be described. As describedabove, the exhaust gas inflow side of the purification inlet pipe 36 ofthe purification casing 38 is fastened to the outlet portion of theexhaust manifold 7. Exhaust gas of the exhaust manifold 7 is supplied tothe exhaust gas purifier 2 through the purification inlet pipe 36. Theexhaust manifold 7 also serves as a casing support body to support theexhaust gas purifier 2. In this case, the exhaust manifold 7 supports amiddle portion of the purification casing 38 in the longitudinaldirection through the purification inlet pipe 36.

As shown in FIGS. 8 to 10, and 16 in detail, the engine 1 includes aninlet-side bracket body 71 and an outlet-side bracket body 72 to supportand secure the exhaust gas purifier 2. The inlet-side bracket body 71and the outlet-side bracket body 72 are formed to be wide in a directionintersecting the output shaft 3 of the engine 1. The inlet-side bracketbody 71 and the outlet-side bracket body 72 are detachably secured tothe cylinder head 5 of the engine 1. The inlet-side bracket body 71 andthe outlet-side bracket body 72 stand separately on the front side andthe rear side of the cylinder head 5 in the direction intersecting theoutput shaft 3. The inlet-side bracket body 71, which is located on therear side of the cylinder head 5, supports the exhaust upstream side ofthe purification casing 38. The outlet-side bracket body 72, which islocated on the front side of the cylinder head 5, supports the exhaustdownstream side of the purification casing 38. The inlet-side bracketbody 71 and the outlet-side bracket body 72 are equivalent to mountingbases.

As shown in FIGS. 9, 12, and 14 to 16, as described above, theinlet-side bracket body 71 is located on the rear side of the cylinderhead 5 (above the mounting plate 10). A lower end of the inlet-sidebracket body 71 is fastened by bolts to a rear surface of the cylinderhead 5. An extension bracket 76 is fastened by bolts to an upper end ofthe inlet-side bracket body 71. A distal end of the extension bracket 76is fastened, through bolts and nuts, to the inlet-side lid member 43 toclose the end portion of the purification casing 38 on the exhaustupstream side. As a result, the exhaust upstream side of thepurification casing 38 is detachably secured to the rear surface of thecylinder head 5 through the inlet-side bracket body 71.

As shown in FIGS. 10 to 15, as described above, the outlet-side bracketbody 72 is located on the front side of the cylinder head 5 (on thecooling fan 9 side). The outlet-side bracket body 72 in this embodimentis separated into an intake-side bracket 91 and an exhaust-side bracket92.

A lower end of the intake-side bracket 91 is fastened by bolts to thefront side of the cylinder head 5. A reinforcement bracket 93 isfastened by bolts to the upper surface of the intake manifold 6. Theintake-side bracket 91 and the reinforcement bracket 93 are fastened bybolts to each other in such a manner that a front side of thereinforcement bracket 93 is disposed over a vertically middle portion ofthe rear surface of the intake-side bracket 91. It should be noted thata first hanger 81, which will be described later, is attached to avertically middle portion of the front surface of the intake-sidebracket 91. In this case, the first hanger 81, the intake-side bracket91, and the reinforcement bracket 93 are fastened together in such amanner that the vertically middle portion of the intake-side bracket 91is clamped between the reinforcement bracket 93 and the first hanger 81.

The exhaust-side bracket 92 includes a front frame 94 having anapproximate C-shape opened downwardly. A rear frame 95 of a plate havinga cross-section slightly folded horizontally in the middle is welded toa rear surface of the front frame 94. In this embodiment, a proximal endof the front frame 95 is fastened by bolts to a bracket fasteningportion 54 a of an outlet clamping flange 54 on the purification casing38 through a spacer 96. That is, one end of the exhaust gas purifier 2is coupled to the exhaust-side bracket 92. It should be noted that,depending on a mounting position of the exhaust gas purifier 2 withrespect to the engine 1, one end of the exhaust gas purifier 2 may becoupled to the intake-side bracket 91.

As shown in FIGS. 10, 11, 13, and 15, a stud bolt 97 serving as anengagement shaft is disposed on a distal end side of the front frame 94of the exhaust-side bracket 92. The stud bolt 97 protrudes forwardlyfrom the front surface of the front frame 94. A provisional fasteningnotch 98 opened upwardly is formed in an upper end of the intake-sidebracket 91. Specifically, a bolt hole for inserting the stud bolt 97formed in the upper end of the intake-side bracket 91 is notched to beopened upwardly, thereby forming the provisional fastening notch 98. Thestud bolt 97 of the front frame 94 is to engage with the provisionalfastening notch 98 on the upper end of the intake-side bracket 91. Adistal end of the front surface of the front frame 94 of theexhaust-side bracket 92 is disposed over the upper end of the rearsurface of the intake-side bracket 91, and the stud bolt 97 is engagedwith the provisional fastening notch 98. Thus, the exhaust-side bracket92 with the purification casing 38 above is supported by the intake sidebracket 91.

The stud bolt 97 and the provisional fastening notch 98 are engaged witheach other to hold the exhaust downstream side of the purificationcasing 38 at a predetermined position. Specifically, the engagement ofthe stud bolt 97 and the provisional fastening notch 98 facilitatespositioning of the exhaust-side bracket 92 with respect to theintake-side bracket 91, and at the same time, positioning of the exhaustgas purifier 2 with respect to the engine 1. It should be noted that,contrary to this embodiment, the stud bolt 97 may be disposed on theintake-side bracket 91, and the provisional fastening, notch 98 may beformed in the exhaust-side bracket 92. An opening direction of theprovisional fastening notch 98 may be set based on the positionalrelationship with the stud bolt 97, and will not be limited to theupward direction.

As shown in FIG. 15, while the stud bolt 97 is engaged with theprovisional fastening notch 98, the distal end of the front surface ofthe front frame 94 of the exhaust-side bracket 92 and the upper end ofthe rear surface of the intake-side bracket 91 are fastened to eachother by bolts. Then, an engagement nut 99 is tightened on the stud bolt97 (additional tightening is performed) to couple the one end of theintake-side bracket 91 and the one end of the exhaust-side bracket 92 toeach other. The lower end of the rear frame 95 of the exhaust-sidebracket 92 is fastened by bolts to a front portion of the left sidesurface of the cylinder head 5. As a result, the exhaust downstream sideof the purification casing 38 is detachably secured to the front surfaceand the front portion of the left side surface (the front side) of thecylinder head 5 through the outlet-side bracket body 72.

With this configuration, the engagement of the stud bolt 97 and theprovisional fastening notch 98 facilitates positioning of theexhaust-side bracket 92 with respect to the intake-side bracket 91, andat the same time, positioning of the exhaust gas purifier 2 with respectto the engine 1. Furthermore, there is no need to execute assemblingoperation such as bolt fastening and disassembling operation whilesustaining the whole weight of the exhaust gas purifier 2. Thissignificantly reduces labor and time at the time of mounting anddismounting operation of the exhaust gas purifier 2 and assembling anddisassembling operation of the exhaust gas purifier 2.

As is apparent from the above description and FIGS. 10 to 15, theintake-side bracket 91 and the exhaust-side bracket 92 are provided asone of the mounting bases to support one end of the exhaust gas purifier2 (outlet-side bracket body 72). The one end of the intake-side bracket91 and the one end of the exhaust-side bracket 92 are fastened to eachother whereas the other end of the intake-side bracket 91 and the otherend of the exhaust-side bracket 92 are coupled to the engine 1 (cylinderhead 5) side. Consequently, the mounting base (outlet-side bracket body72) is separated into the intake-side bracket 91 and the exhaust-sidebracket 92. While the brackets 91 and 92 as single parts are reduced inweight, the brackets 91 and 92 are fastened to each other to secure asufficient strength of support, which enables the exhaust gas purifier 2to be stably mounted on the engine 1. This therefore preventsdegradation and damage of the exhaust gas purifier 2 due to vibration ofthe engine 1, for example. Thus, durability of the exhaust gas purifier2 is improved.

As is apparent from the above description and FIGS. 10 to 15, one end ofthe exhaust gas purifier 2 is coupled to one of the intake-side bracket91 and the exhaust-side bracket 92. Consequently, the exhaust gaspurifier 2 is mounted on or dismounted from the engine 1 while one ofthe intake-side bracket 91 and the exhaust-side bracket 92 is coupled tothe one end of the exhaust gas purifier 2. This improves assemblingworkability of the exhaust gas purifier 2 with respect to the engine 1.Moreover, the other of the intake side bracket 91 and the exhaust-sidebracket 92 may be used for a mounting base of the hanger 81 to hang theengine 1.

As is apparent from the above description and FIGS. 10 to 15, theprovisional fastening notch 98 is formed in one of the intake sidebracket 91 and the exhaust-side bracket 92. The engagement shaft 97,which is disposed on the other of the intake-side bracket 91 and theexhaust-side bracket 92, is to engage with the provisional fasteningnotch 98. Therefore, the engagement of the engagement shaft 97 and theprovisional fastening notch 98 facilitates positioning of one of thebrackets 91 (92) with respect to the other bracket 92 (91), and at thesame time, positioning of the exhaust gas purifier 2 with respect to theengine 1. Furthermore, there is no need to execute assembling operationsuch as bolt fastening and disassembling operation while sustaining thewhole weight of the exhaust gas purifier 2. This significantly reduceslabor and time at the time of mounting and dismounting operation of theexhaust gas purifier 2 and assembling and disassembling operation of theexhaust gas purifier 2.

In particular, as described above, the lower ends of the inlet-sidebracket body 71 and the outlet-side bracket body 72 are fastened to thecylinder head 5 to set a mounting reference position of the exhaust gaspurifier 2 with respect to the engine 1 highly accurately. Therefore,although the exhaust gas purifier 2 has a larger weight than apost-processing device such as a muffler, the exhaust gas purifier 2 ismounted at a predetermined position appropriately.

Next, referring to FIGS. 6 to 12, and 16, hangers 81 and 82 used formounting and dismounting the engine 1 on and from the working machineand an attachment configuration of the hangers 81 and 82 will bedescribed. The engine 1 in this embodiment includes a pair of hangers 81and 82. In order to lift the engine 1 with the exhaust gas purifier 2,which has a large weight, in a stable posture (in a balanced manner),the pair of hangers 81 and 82 are separately disposed on both sides ofthe engine 1 in a direction intersecting the output shaft 3. The pair ofhangers 81 and 82 in this embodiment are separately disposed on thefront side and the rear side of the cylinder head 5 of the engine 1. Ofthe pair of hangers 81 and 82, the second hanger 82 is made of alongitudinal metal plate. A through hanging hole 86 through which, forexample, wire rope is inserted is formed in an upper end of the secondhanger 82. A lower end of the second hanger 82 is fastened by bolts tothe rear surface of the cylinder head 5.

The first hanger 81 is also made of a longitudinal metal plate. Athrough hanging hole 83 through which, for example, wire rope isinserted is formed in an upper end of the first hanger 81. The lower endof the second hanger 82 is fastened by bolts to the rear surface of thecylinder head 5. A lower end of the first hanger 81 is fastened by boltsto the intake-side bracket 91. In this case, the reinforcement bracket93 fastened by bolts to the upper surface of the intake manifold 6 andthe lower end of the first hanger 81 clamp a vertically middle portionof the intake-side bracket 91. In this clamped state, the first hanger81, the intake-side bracket 91, and the reinforcement bracket 93 arefastened together. It should be noted that, contrary to this embodiment,the first hanger 81 may be disposed on the exhaust-side bracket 92.

The strength of the first hanger 81 is set to be smaller than strengthsof the intake-side bracket 91 and the reinforcement bracket 93. When anexcessively large external force is exerted at the time of, for example,lifting the engine 1, plastic deformation or breakage of the firsthanger 81 may be induced faster than the intake-side bracket 91 and thereinforcement bracket 93. This setting of strength of the first hanger81 prevents deformations of the intake-side bracket 91 and thereinforcement bracket 93 by lifting of the engine 1. As a result,exertion of external force on the exhaust gas purifier 2 is minimized atthe time of lifting of the engine 1.

In the above-described configuration, when the engine 1 is mounted onand dismounted from the working machine, wire rope, for example, isinserted through the through hanging holes 83 and 86 formed in the firstand second hangers 81 and 82, and the wire rope is engaged with such acomponent as a hook of a chain block. Thus, the engine 1 is lifted.

As is apparent from the above description and FIGS. 6 to 10, the lowerend of the hanger 81 to lift the engine 1 is fastened to one of theintake-side bracket 91 and the exhaust-side bracket 92. Consequently,one of these two brackets 91 and 92, which are highly rigid componentsto support the exhaust gas purifier is also used for a fastening portionof the hanger 81. This reduces the number of components, and at the sametime, the hanger 81 is firmly fastened to the engine 1 (the couplingstrength of the hanger 81 with respect to the engine 1 is secured).

Next, referring to FIGS. 17 and 18, a configuration adjacent to theflywheel 11 and the mounting plate 10 will be described. As describedabove, the mounting plate 10 is disposed on one side surface of theengine 1 intersecting the output shaft 3 (specifically, the rear surfaceof the cylinder block 4). The flywheel 11 is disposed over the mountingplate 10. The flywheel 11 is axially supported on the output shaft 3.Therefore, the mounting plate 10 is located between the rear surface ofthe cylinder block 4 and the flywheel 11.

A recessed portion 121 is formed in an inner surface of the flywheel 11close to the engine 1 (cylinder block 4). An annular pulser 122 for theoutput shaft is disposed in the recessed portion 121. In this case, anengagement stepped portion 123 for the pulser is formed in the recessedportion 121 and protrudes toward the rear surface of the cylinder block4 in the direction of the output shaft 3. The output shaft pulser 122 ispress fitted or shrink fitted in the pulser engagement stepped portion123. The ring gear 124 to engage with the engine starter 18 is disposedon an outer peripheral portion on the inner surface side of the flywheel11 close to the engine 1 (cylinder block 4). An engagement steppedportion 125 for the gear is formed on an outer peripheral portion on theinner surface side of the flywheel 11. The ring gear 124 is press fittedor shrink fitted in the gear engagement stepped portion 125. Therefore,the output shaft pulser 122 and the ring gear 124 are fitted and securedto the flywheel 11 from the same side (the inner surface side close tothe engine 1).

Output protrusions 122 a are formed on an outer peripheral surface ofthe output shaft pulser 122, and serve as portions to be detected whichare disposed at intervals of a predetermined rotation angle (crankangle). A non-toothed portion 122 b is formed on a portion of the outerperipheral surface of the output shaft pulser 122 corresponding to thetop dead center (TDC) of, for example, the first or fourth cylinder. Arotation angle sensor 126 serving as a rotation angle detection memberis disposed on a right side portion of the mounting plate 10. A distalend (detection side) of the rotation angle sensor 126 is inserted intothe recessed portion 121, and opposed to the output protrusions 122 aand the non-toothed portion 122 b on the outer peripheral portion of theoutput shaft pulser 122 on the inner side. The rotation angle sensor 126detects a rotation angle (crank angle) of the output shaft 3. Along withrotation of the output shaft 3, the output protrusions 122 a of theoutput shaft pulser 122 pass the vicinity of the rotation angle sensor126. Thus, a rotation angle signal is output.

The engine starter 18 with an output shaft having a pinion gear 127 isdisposed on the left side of the mounting plate 10. The pinion gear 127of the engine starter 18 meshes with the ring gear 124 of the flywheel11. When the engine 1 is started, torque of the engine starter 18 causesthe ring gear 124 of the flywheel 11 to rotate to make the output shaft3 start rotating (so-called cranking is executed).

Conventionally, in an engine apparatus mounted on a working machine, arotation angle signal is output from a rotation angle sensor inaccordance with rotation of an output shaft (crank shaft) of an engine.A cam angle signal is output from a cam angle sensor in accordance withrotation of a cam shaft. A cylinder is discriminated based on acombination of the rotation angle signal and the cam angle signal. Basedon a result of the cylinder discrimination, fuel injection and ignitionof each of the cylinders are executed. The engine is driven by such fuelinjection and ignition of each of the cylinders (see, for example,Japanese Unexamined Patent Application Publication No. 2010-261322).Here, cylinder discrimination means specifying a rotation angle(rotation position) of the output shaft in one cycle (720° CA) in theengine.

In this kind of the engine apparatus, a flywheel is disposed on one sideportion of the engine in a direction of the output shaft and integrallyrotates with the output shaft. The rotation angle sensor is disposedadjacent to an outer peripheral side of an output shaft pulser attachedto the flywheel. Normally, a flywheel housing is disposed on one sideportion of the engine in the direction of the output shaft. The flywheelis accommodated in the flywheel housing. The rotation angle sensor isdisposed on the outer peripheral side of the flywheel housing andopposed to the output shaft pulser. In accordance with rotation of theoutput shaft, portions to be detected of the output shaft pulser passthe vicinity of the rotation angle sensor. Thus, the rotation anglesensor outputs the rotation angle signal.

In the conventional configuration, however, the flywheel is accommodatedin the flywheel housing, and the rotation angle sensor is disposed onthe outer peripheral side of the flywheel housing. Accordingly, thethickness of the flywheel housing in the direction of the output shaftis inevitably increased. The weight of the whole engine apparatus isincreased by the weight of the flywheel housing. This also increases thesize of the engine apparatus disadvantageously.

In the above-described embodiment, contrary to the conventionalconfiguration, the engine apparatus includes the rotation angledetection member 126 and the output shaft pulser 122. The rotation angledetection member 126 detects a rotation angle of the output shaft 3 ofthe engine 1. The output shaft pulser 122 is disposed on the flywheel 11of the engine 1. The mounting plate 10 supporting the engine starter 18is disposed on one side portion of the engine 1 on the flywheel 11 side.The mounting plate 10 is disposed between the one side portion of theengine 1 and the flywheel 11. The rotation angle detection member 126 isdisposed on the mounting plate 10. The rotation angle detection member126 is opposed to the side surface of the output shaft pulser 122 thatfaces the one side portion of the engine 1. Consequently, the rotationangle detection member 126 is supported on the mounting plate 10 havinga weight smaller than the flywheel housing, and the heavy flywheelhousing is unnecessary. Therefore, the engine 1 is reduced in weight andsize.

As is apparent from the above description, and FIGS. 17 and 18, therecessed portion 121 is formed in the inner surface of the flywheel 11close to the engine 1. The output shaft pulser 122 is disposed in therecessed portion 121. The distal end of the rotation angle detectionmember 126 is inserted into the recessed portion 121. Consequently, theoutput shaft pulser 122 and the rotation angle detection member 126 arearranged on the flywheel 11 and the mounting plate 10 in a compactspace. This decreases the thickness of the flywheel 11 and the mountingplate 10 in the direction of the output shaft 3, thus contributing tospace saving of the engine 1 and surrounding components.

As is apparent from the above description, and FIGS. 17 and 18, the ringgear 124 to engage with the engine starter 18 is disposed on the outerperipheral portion of the inner surface of the flywheel 11 close to theengine 1. The output shaft pulser 122 and the ring gear 124 are fittedand secured to the flywheel 11 from the same side. Consequently, theoutput shaft pulser 122 and the ring gear 124 are located between theflywheel 11 and the mounting plate 10. This minimizes entering of dustand foreign matter into the vicinity of the output shall pulser 122 andthe ring gear 124.

It should be noted that the configurations of the components of thepresent invention should not be limited to the embodiment illustrated inthe drawings. Various modifications are possible within the scope of thepresent invention.

DESCRIPTION OF THE REFERENCE NUMERAL

-   1 Engine-   2 Exhaust gas purifier-   3 Output shaft-   4 Cylinder block-   18 Engine starter-   71 inlet-side bracket body-   72 Outlet-side bracket body-   81 First hanger-   82 Second hanger-   91 Intake-side bracket-   92 Exhaust-side bracket-   97 Stud bolt-   98 Provisional fastening notch-   121 Recessed portion-   122 Output shaft puller-   124 Ring gear-   126 Rotation angle sensor (rotation angle detection member)

The invention claimed is:
 1. An engine apparatus comprising: an enginecomprising an intake manifold, an exhaust manifold, cylinder head, andan output shaft; an exhaust gas purifier configured to purify exhaustgas of the engine and supported over the engine at least threelocations; and mounting bases located at an upper side of the engine andwhich support the exhaust gas purifier; wherein the intake manifold andthe exhaust manifold are distributed on two side surfaces along anoutput shaft of the engine; wherein the exhaust gas purifier is disposedon an upper side of the engine through the mounting bases, so as toextend in parallel to the output shaft of the engine; wherein theexhaust manifold connects to an entrance tube of the exhaust gaspurifier provided in a longitudinal middle portion of the exhaust gaspurifier, so that the exhaust manifold provides one location of supportvia the purifier entrance tube; wherein each one of the mounting basescomprise a bracket body that supports a corresponding end of the exhaustgas purifier to provide a second location and a third location ofsupport; wherein the bracket body of a first one of the mounting basesat one end of the exhaust gas purifier comprises an intake-side bracketand an exhaust-side bracket, a first end of the intake-side bracketbeing connected to a first end of the exhaust-side bracket above theengine, and an opposite end of the intake-side bracket and an oppositeend of the exhaust-side bracket being connected to the engine's cylinderhead; wherein said one end of the exhaust gas purifier is coupled to oneof the intake-side bracket and the exhaust-side bracket; and wherein aprovisional fastening notch is formed in one of the intake-side bracketand exhaust-side bracket, and an engagement shaft is disposed on theother of the intake-side bracket and the exhaust-side bracket, saidengagement shaft engaging in the provisional fastening notch.
 2. Theengine apparatus according to claim 1, wherein a lower end of a hangerconfigured to lift the engine is fastened to one of the intake-sidebracket and the exhaust-side bracket.
 3. The engine apparatus accordingto claim 1, further comprising: a rotation angle detection memberconfigured to detect a rotation angle of the output shaft of the engine;and an output shaft pulser disposed on a flywheel of the engine, whereinthe rotation angle detection member is disposed on a mounting plate thatsupports an engine starter, and is opposed to a side surface of theoutput shaft pulser facing a side portion of the engine on a flywheelside of the engine where the mounting plate is disposed.
 4. The engineapparatus according to claim 3, wherein a recessed portion is formed inan inner surface of the flywheel close to the engine, the output shaftpulser being disposed in the recessed portion, with a distal end of therotation angle detection member being inserted into the recessedportion.
 5. The engine apparatus according to claim 3, wherein a ringgear to engage with the engine starter is disposed on an outerperipheral portion of the inner surface of the flywheel close to theengine, the output shaft pulser and the ring gear being fitted andsecured to the flywheel from a same side.